Field of the Invention
The present invention relates to an outer tube, and particularly relates to an outer tube including two insertion holes in which an insertion part of an endoscope and an insertion part of a treatment tool can move back and forth.
Description of the Related Art
Endoscopic surgery to inset an endoscope and a treatment tool such as a laparoscope in an abdominal cavity through an outer tube tapped into an abdominal wall and treat a lesion site has become widespread in recent years. Since an operative wound in this endoscopic surgery is smaller than an abdominal surgery, it is possible to shorten a postoperative bed rest period.
In the endoscopic surgery, gas is supplied into the abdominal cavity beforehand to expand the abdominal cavity, and an observational region of the endoscope and a treatment region of the treatment tool are secured. Therefore, an airtight valve that prevents a gas leak is included in the outer tube.
Japanese National Publication of International Patent Application No. 7-509626 (hereinafter referred to as PTL 1) suggests a valve member (valve structure) which is provided in an outer tube (insertion instrument assembly) and in which a slit and opening (hole) forming an airtight valve are integrally configured. This valve member is disposed in a cap provided in the proximal end of an outer tube body (cannula). Here, the outer tube body in PTL 1 includes an insertion hole to move one treatment tool back and forth but does not include two insertion holes to move two treatment tools back and forth.
On the other hand, an outer tube disclosed in PTL 2 includes multiple insertion holes (lumens) in an outer tube body (body tube). According to this outer tube, since it is possible to insert multiple treatment tools by using the multiple insertion holes, it is possible to reduce the number of outer tubes tapped into an abdominal wall. By this means, it is possible to reduce invasion added to the body wall.
Moreover, an outer tube in Japanese Utility Model Laid-Open No. 7-13301 (hereinafter, referred to as PTL 2) can insert a treatment tool and an endoscope in one outer tube body.
In addition, in PTL 2, a cap is provided in the proximal end of the outer tube body, and a valve member including an elastic sheet is attached to this cap. The valve member includes a straight line (minus)-shaped slit in a position corresponding to each insertion hole. The insertion part of the treatment tool or the endoscope is internally fitted to the slit and moved backward relative to each insertion hole. When the insertion part is internally fitted to the slit, the slit closely contacts with the outside surface of the insertion part. Moreover, at the time of non-insertion (removal) at which the insertion part is not internally fitted to the slit, the slit is closed. By this means, since an airtight state is maintained, it is possible to prevent gas in a body cavity from leaking outside through the outer tube.
Furthermore, in a cross section vertical to the axial direction of the outer tube body, two insertion holes in PTL 2 are formed in a cross-sectional D-shaped (semicircle) via a partition wall formed in a straight shape in the central part. Further, the slit of the valve member in PTL 2 is formed in parallel to the partition wall.